"planet Venus, that probably dates as early as the second millennium BC. The MUL.APIN is a pair of cuneiform tablets dating from the 7th century BC that lays out the motions of the Sun, Moon, and planets over the course of the year. The Babylonian astrologers also laid the foundations of what would eventually become Western astrology. The ""Enuma anu enlil"", written during the Neo-Assyrian period in the 7th century BC, comprises a list of omens and their relationships with various celestial phenomena including the motions of the planets. Venus, Mercury, and the outer planets Mars, Jupiter, and Saturn were"
"Venus Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. It has the longest rotation period (243 days) of any planet in the Solar System and rotates in the opposite direction to most other planets (meaning the Sun would rise in the west and set in the east). It does not have any natural satellites. It is named after the Roman goddess of love and beauty. It is the second-brightest natural object in the night sky after the Moon, reaching an apparent magnitude of −4.6 – bright enough to cast shadows at night and, rarely,"
"heights. Venus Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. It has the longest rotation period (243 days) of any planet in the Solar System and rotates in the opposite direction to most other planets (meaning the Sun would rise in the west and set in the east). It does not have any natural satellites. It is named after the Roman goddess of love and beauty. It is the second-brightest natural object in the night sky after the Moon, reaching an apparent magnitude of −4.6 – bright enough to cast shadows at night and,"
"Saturn Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius about nine times that of Earth. It has only one-eighth the average density of Earth, but with its larger volume Saturn is over 95 times more massive. Saturn is named after the Roman god of agriculture; its astronomical symbol (♄) represents the god's sickle. Saturn's interior is probably composed of a core of iron–nickel and rock (silicon and oxygen compounds). This core is surrounded by a deep layer of metallic hydrogen, an intermediate"
"Eleventh planet Eleventh planet (of the Solar System) may refer to Vesta, the eleventh object to be named a planet, later to be reclassified as an asteroid; Uranus, the eleventh planet from the Sun upon Vesta's discovery, though this was quickly superseded by new discoveries; or Haumea, which would be the eleventh planet if the classification advocated by Alan Stern ""et al."" were adopted; or Makemake, which would be the eleventh planet in terms of distance from the Sun, as opposed to order of discovery. The eleventh planet in the early 19th century was Uranus by order of distance from"
"in the image, with bits going to the right and more significant digits below. Earth The solar system, showing the Sun and the planets in the order of their position from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. (Pluto has since been reclassified as a dwarf planet by the International Astronomical Union, but it was still considered a planet at the time the message was transmitted.) The Earth is the third planet from the Sun; its graphic is shifted up to identify it as the planet from which the signal was sent. Additionally, the human"
"Neptune Neptune is the eighth and farthest known planet from the Sun in the Solar System. In the Solar System, it is the fourth-largest planet by diameter, the third-most-massive planet, and the densest giant planet. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times the mass of Earth and slightly larger than Neptune. Neptune orbits the Sun once every 164.8 years at an average distance of . It is named after the Roman god of the sea and has the astronomical symbol ♆, a stylised version of the"
"the Sun: Jupiter is the largest, at 318 Earth masses, whereas Mercury is the smallest, at 0.055 Earth masses. The planets of the Solar System can be divided into categories based on their composition: An exoplanet (extrasolar planet) is a planet outside the Solar System. In early 1992, radio astronomers Aleksander Wolszczan and Dale Frail announced the discovery of two planets orbiting the pulsar PSR 1257+12. This discovery was confirmed, and is generally considered to be the first definitive detection of exoplanets. These pulsar planets are believed to have formed from the unusual remnants of the supernova that produced the"
"from orbit or destroy them on short timescales relative to the age of the system. 55 Cancri b 55 Cancri b (abbreviated 55 Cnc b), occasionally designated 55 Cancri Ab (to distinguish it from the star 55 Cancri B), also named Galileo, is an exoplanet orbiting the Sun-like star 55 Cancri A every 14.65 days. It is the second planet in order of distance from its star, and is an example of a hot Jupiter, or possibly rather ""warm Jupiter"". In July 2014 the International Astronomical Union launched a process for giving proper names to certain exoplanets and their host"
"define the term ""planet"" formally in 2006, during their 26th General Assembly. That definition excluded Pluto and reclassified it as a dwarf planet. Pluto is the largest and second-most-massive known dwarf planet in the Solar System, and the ninth-largest and tenth-most-massive known object directly orbiting the Sun. It is the largest known trans-Neptunian object by volume but is less massive than Eris. Like other Kuiper belt objects, Pluto is primarily made of ice and rock and is relatively small—about one-sixth the mass of the Moon and one-third its volume. It has a moderately eccentric and inclined orbit during which it"
"candidate sites had little or no possibility of being the results of the proposed impacts. More recent discoveries include the following: Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a giant planet with a mass one-thousandth that of the Sun, but two-and-a-half times that of all the other planets in the Solar System combined. Jupiter and Saturn are gas giants; the other two giant planets, Uranus and Neptune, are ice giants. Jupiter has been known to astronomers since antiquity. It is named after the Roman god Jupiter. When viewed from"
"Sun. It is also rather metal-rich, having about 70% more ""metals"" (elements heavier than helium) than the Sun, which is typical for stars with extrasolar planets. The secondary star (Gliese 777B) is a distant, dim red dwarf star orbiting the primary at a distance of 3,000 astronomical units. One orbit takes at least tens of thousands of years to complete. The star itself may be a binary, the secondary being a very dim red dwarf. Not much information is available on the star system. In 2002 a discovery of a long-period, wide-orbiting planet (Gliese 777b) was announced by the Geneva"
"Uranus Uranus (from the Latin name ""Ūranus"" for the Greek god Οὐρανός) is the seventh planet from the Sun. It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System. Uranus is similar in composition to Neptune, and both have bulk chemical compositions which differ from that of the larger gas giants Jupiter and Saturn. For this reason, scientists often classify Uranus and Neptune as ""ice giants"" to distinguish them from the gas giants. Uranus' atmosphere is similar to Jupiter's and Saturn's in its primary composition of hydrogen and helium, but it contains more ""ices"" such as"
"Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System after Mercury. In English, Mars carries a name of the Roman god of war, and is often referred to as the ""Red Planet"" because the reddish iron oxide prevalent on its surface gives it a reddish appearance that is distinctive among the astronomical bodies visible to the naked eye. Mars is a terrestrial planet with a thin atmosphere, having surface features reminiscent both of the impact craters of the Moon and the valleys, deserts, and polar ice caps of Earth. The rotational period"
"be abandoned, and a vogue for accurate, realist depictions of human colonies on Mars developed, the best known of which may be Kim Stanley Robinson's ""Mars"" trilogy. Pseudo-scientific speculations about the Face on Mars and other enigmatic landmarks spotted by space probes have meant that ancient civilizations continue to be a popular theme in science fiction, especially in film. Images Videos Cartographic resources Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System after Mercury. In English, Mars carries a name of the Roman god of war, and is often referred to as"
"Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a giant planet with a mass one-thousandth that of the Sun, but two-and-a-half times that of all the other planets in the Solar System combined. Jupiter and Saturn are gas giants; the other two giant planets, Uranus and Neptune, are ice giants. Jupiter has been known to astronomers since antiquity. It is named after the Roman god Jupiter. When viewed from Earth, Jupiter can reach an apparent magnitude of −2.94, bright enough for its reflected light to cast shadows, and making it"
"55 Cancri b 55 Cancri b (abbreviated 55 Cnc b), occasionally designated 55 Cancri Ab (to distinguish it from the star 55 Cancri B), also named Galileo, is an exoplanet orbiting the Sun-like star 55 Cancri A every 14.65 days. It is the second planet in order of distance from its star, and is an example of a hot Jupiter, or possibly rather ""warm Jupiter"". In July 2014 the International Astronomical Union launched a process for giving proper names to certain exoplanets and their host stars. The process involved public nomination and voting for the new names. In December 2015,"
"Fifth planet (hypothetical) In the history of astronomy, a handful of Solar System bodies have been counted as the fifth planet from the Sun. Under the present definition of a planet, Jupiter is counted as the fifth. There are three main ideas regarding hypothetical planets between Mars and Jupiter. During the early 19th century, as asteroids were discovered, they were considered planets. Jupiter became the sixth planet with the discovery of Ceres in 1801. Soon, three more asteroids, Pallas (1802), Juno (1804), and Vesta (1807) were discovered. They were counted as separate planets, despite the fact that they shared an"
"preventing it from interacting directly with its atmosphere and instead creating its own region, called a magnetosphere, composed of a plasma very different from that of the solar wind. The magnetosphere of Saturn is the second–largest magnetosphere in the Solar System after that of Jupiter. As with Earth's magnetosphere, the boundary separating the solar wind's plasma from that within Saturn's magnetosphere is called the magnetopause. The magnetopause distance from the planet's center at the subsolar point varies widely from 16 to 27 R (R=60,330 km is the equatorial radius of Saturn). The magnetopause's position depends on the pressure exerted by"
"Since the dawn of the Space Age, close observation by space probes has found that Earth and the other planets share characteristics such as volcanism, hurricanes, tectonics, and even hydrology. Planets are generally divided into two main types: large low-density giant planets, and smaller rocky terrestrials. There are eight planets in the Solar System. In order of increasing distance from the Sun, they are the four terrestrials, Mercury, Venus, Earth, and Mars, then the four giant planets, Jupiter, Saturn, Uranus, and Neptune. Six of the planets are orbited by one or more natural satellites. Several thousands of planets around other"
"a second outer planet perturbing HAT-P-2 b, although thus far, this has neither been proven or disproven. HAT-P-2b HAT-P-2b is an extrasolar planet detected by the HATNet Project in May 2007. It orbits a class F star, (bigger and hotter than the Sun), located about 420 light-years away in the constellation Hercules. Every 5 days 15 hours, it crosses directly in front of the star as viewed from Earth. The planet's mass has been estimated to be 8.65 times that of Jupiter, while its diameter, at , is 0.951 times Jupiter's. Its small size, despite the bloating of the planet's"
"2 Pallas Pallas (minor-planet designation: 2 Pallas) is the second asteroid to have been discovered (after Ceres), and is one of the largest asteroids in the Solar System. With an estimated 7% of the mass of the asteroid belt, it is the third-most-massive asteroid, being 10–30% less massive than Vesta. It is in diameter, somewhat smaller than 4 Vesta. It is likely a remnant protoplanet. When Pallas was discovered by the German astronomer Heinrich Wilhelm Matthäus Olbers on 28 March 1802, it was counted as a planet, as were other asteroids in the early 19th century. The discovery of many"
"moon Triton to be investigated around 2029. The proposed ""New Horizons 2"" mission (which was later scrapped) might also have done a close flyby of the Neptunian system. Neptune Neptune is the eighth and farthest known planet from the Sun in the Solar System. In the Solar System, it is the fourth-largest planet by diameter, the third-most-massive planet, and the densest giant planet. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times the mass of Earth and slightly larger than Neptune. Neptune orbits the Sun once every 164.8"
"Ultraviolet light is strongly attenuated by Earth's ozone layer, so that the amount of UV varies greatly with latitude and has been partially responsible for many biological adaptations, including variations in human skin color in different regions of the Earth. The Sun has eight known planets. This includes four terrestrial planets (Mercury, Venus, Earth, and Mars), two gas giants (Jupiter and Saturn), and two ice giants (Uranus and Neptune). The Solar System also has at least five dwarf planets, an asteroid belt, numerous comets, and a large number of icy bodies which lie beyond the orbit of Neptune. Sun The"
"the ""New Horizons"" space probe in June 2015. Under this definition, the Earth–Moon system is not currently a double planet; although the Moon is massive enough to cause the Earth to make a noticeable revolution around this center of mass, this point nevertheless lies well within Earth. However, the Moon migrates outward from Earth at a rate of approximately per year; in a few hundred million years, the Earth–Moon system's center of mass will lie outside Earth, which would make it a double-planet system. The center of mass of the Jupiter–Sun system lies outside the surface of the Sun, though"
"Outer planets The outer planets are those planets in the Solar System beyond the asteroid belt, and hence refers to the gas giants and ice giants, which are in order of their distance from the Sun: The outer planets all have ring systems, although all but Saturn's are faint when viewed from Earth. Another aspect common to the gas giants is their many natural satellites (moons), two of which are larger than the planet Mercury (Jupiter's Ganymede and Saturn's Titan). That pair and Io, Callisto, Europa, and Triton, are larger than Pluto and Eris. This region of space is also"
"that this could be due to the gravitational influence of a second planet in the system at a distance of several astronomical units (AU). Confirmation of the existence of a second planet, HD 217107 c, followed in 2005. HD 217107 b HD 217107 b is an extrasolar planet approximately 64 light-years away from Earth in the constellation of Pisces (the Fish). The planet was discovered orbiting the star HD 217107 approximately every seven days, classifying the planet as a hot Jupiter. Because of the planet's somewhat eccentric orbit, scientists were able to confirm another planet within the system (HD 217107"
"initially named after Ceres, but when cerium was named, its discoverer changed the name to palladium, after the second asteroid, 2 Pallas. The categorization of Ceres has changed more than once and has been the subject of some disagreement. Johann Elert Bode believed Ceres to be the ""missing planet"" he had proposed to exist between Mars and Jupiter, at a distance of 419 million km (2.8 AU) from the Sun. Ceres was assigned a planetary symbol, and remained listed as a planet in astronomy books and tables (along with 2 Pallas, 3 Juno, and 4 Vesta) for half a century."
"to less than 0.01% of the Earth's mass. However, this does not exclude the presence of an asteroid belt or a Kuiper belt equivalent. The secondary, 55 Cancri B, is a red dwarf star much less massive and luminous than the Sun. There are indications that component B may itself be a double star, though this is uncertain. The 55 Cancri system was the first known to have four, and later five planets, and may possibly have more. The innermost planet, e, transits 55 Cancri A as viewed from Earth. The next planet, b, is non-transiting but there is tentative"
"Sun, it is around 9,160 light-years distant from Earth. AO Cassiopeiae is a binary system composed of an O8 main sequence star and an O9.2 bright giant that respectively weigh anywhere between 20.30 and 57.75 times and 14.8 and 31.73 times the mass of the Sun. The two massive stars are so close to each other they distort each other into egg-shapes. Tycho Brahe's supernova was visible within Cassiopeia, and the star Tycho G is suspected of being the donor of the material that triggered that explosion. If the Earth's Sun could be observed from α Centauri, the closest star"
"from the original solar nebula. The Solar System has four terrestrial planets: Mercury, Venus, Earth, and Mars. Only one terrestrial planet, Earth, is known to have an active hydrosphere. During the formation of the Solar System, there were probably many more terrestrial planetesimals, but most merged with or were ejected by the four terrestrial planets. Dwarf planets, such as Ceres, Pluto and Eris, and small Solar System bodies are similar to terrestrial planets in the fact that they do have a solid surface, but are, on average, composed of more icy materials (Ceres, Pluto and Eris have densities of 2.17,"
"observations. Despite its relatively large angular distance, direct imaging is problematic due to the star–planet contrast. In 2014, a second planet was discovered by astronomers at the University of New South Wales. This one is believed to be of super-Earth mass and has since been given the scientific name Gliese 832 c. It was announced to orbit in the optimistic habitable zone but outside the conservative habitable zone of its parent star. The planet is believed to be in, or very close to, the right distance from its sun to allow liquid water to exist on its surface. If this"
"these elements in so-called Population II, heavy-element-poor, stars. The heavy elements could most plausibly have been produced by endothermic nuclear reactions during a supernova, or by transmutation through neutron absorption within a massive second-generation star. The Sun is by far the brightest object in the Earth's sky, with an apparent magnitude of −26.74. This is about 13 billion times brighter than the next brightest star, Sirius, which has an apparent magnitude of −1.46. The mean distance of the Sun's center to Earth's center is approximately , though the distance varies as Earth moves from perihelion in January to aphelion in"